Sage Grouse Saga

Greater sage grouse, the largest grouse in North America, inhabit sage grasslands of the Intermountain West, from Colorado to the Columbia Plateau and from southern Alberta to southern Utah. Closely tied to their habitat, these grouse feed solely on the sage plant in the winter while supplementing that diet with a variety of forbs, insects and grasses during the warmer months. Unlike many game birds, they do not possess a muscular crop and cannot digest hard seeds.

Come spring, sage grouse gather in clearings (known as leks) at dawn and dusk, where the dominant males attract mates with ritualized strutting, tail fanning and a variety of noises from their air sacs; most of the females mate with only one or two of the performers. Nests are placed on the ground and females are solely responsible for both incubation and protection of the young; six to twelve eggs are generally produced. Able to forage soon after birth, the young are vulnerable to a wide range of predators, including snakes, prairie falcons, crows, magpies, badgers, coyotes, bobcats and owls.

Once abundant across the American West, greater sage grouse have long been threatened by habitat loss; their population, estimated to have been about 16 million in the early 1900s, has fallen to less than 500,000 today, a drop of 97% over the past century. The loss of sage grasslands to mining, ranching and oil production has been primarily responsible for this decline and efforts to list the greater sage grouse as an Endangered Species have been successfully blocked by Western Governors and their Federal colleagues. Perhaps a 99% population decline will be more convincing.

Long-Billed Curlews

While crossing the stormy Plains yesterday afternoon, I encountered a small flock of long-billed curlews, attempting to fly into the teeth of an icy north wind. After wintering along the western Gulf Coast, in South Texas, in Southern California or in Mexico, this largest American shorebird returns to grasslands of the High Plains, Great Basin and Columbia Plateau for the warmer months.

Once on their breeding grounds, couples engage in courtship rituals, including dances, looping flights and preliminary nest site scooping by the male. The female eventually selects one of his open ground sites, engages in additional scooping and collects a variety of plant materials to place in the floor of the depression. Four eggs are deposited and incubated by both parents; like many game birds, the young are able to move about and feed soon after hatching and are attended by both parents for a week or so. Thereafter, the female parent departs to join other wayward mothers and juveniles in large feeding flocks while the father stays to watch over the youngsters until they are fledged. The long, down-curved bill of this curlew is used to probe mudflats, wet meadows and sandy shallows for a variety of invertebrates (worms, insect larvae, shrimp, sand crabs) and small amphibians; they may also snare grasshoppers, crickets and other insects from the grass and occasionally consume the eggs of other prairie birds.

Once common in parts of the Eastern U.S., long-billed curlews have retreated westward due to over-hunting and habitat loss to agriculture; fortunately, the western populations seem to have stabilized but remain sensitive to the health of shortgrass ecosystems. Small numbers of long-billed curlews may turn up on Atlantic beaches during the fall and winter months where they can be distinguished from whimbrels by the curlew's larger size, longer bill and unstriped crown and from the occasional Eurasian curlew by the latter's darker plumage, white rump and heavily streaked breast; the cinnamon wing linings of long-billed curlews also aid identification when this large shorebird is in flight.

Lake Missoula & the Channeled Scablands

Near the end of the Pleistocene Ice Age, about 13,000 years ago, a lobe of the Cordilleran Glacier that covered the Rocky Mountains blocked the flow of the Clark Fork River, in northwestern Montana. Behind this dam of ice, a massive lake developed; 200 miles long and 2000 feet deep, Glacial Lake Missoula contained 500 cubic miles of glacial meltwater.

Eventually, the ice dam failed and a torrent of water rushed across the Idaho Panhandle, eastern Washington and the Columbia River Valley. In fact, as the glacier advanced and retreated over 2500 years, the lake repeatedly formed and drained, eroding the Channeled Scablands of the Columbia Plateau. Characterized by broad, braided canyons, dry falls, rippled rock formations, massive gravel bars and countless erratic boulders, this unique topography attests to the power of the recurrent floods; indeed, the Columbia River Gorge was primarily carved by these torrents.

While similar glacial lake floods occured elsewhere across the Northern Hemisphere (including the Bonneville Flood of southern Idaho), none were as powerful as those arising from Lake Missoula. Geologists and hydrologists estimate that the flow of these deluge events (which numbered three dozen or more) exceeded the current total flow of all rivers on Earth and emptied the Lake within a few days.

Harney Basin

Harney Basin is a geologic and topographic basin in southeast Oregon; while it sits adjacent to the northwest corner of the Great Basin, it is separated from that province by the massive fault-block of the Steens Mountain ridge. On its north side, the Harney Basin is bordered by the southern edge of the Blue Mountains while a high lava plain separates the basin from the watersheds of the John Day and Klamath Rivers to the northwest and southwest, respectively.

During warm interglacial periods of the Pleistocene, glacial meltwater from the adjacent highlands filled the Harney Basin, spilling northeastward into the Malheur River, a tributary of the Snake River. Today, as the climate has warmed through the Holocene, the floor of Harney Basin has become a high desert, receiving only 6 inches of precipitation each year; a low divide along the basin's northeast edge, formerly a spillway, now completes the basin topography and all streams flow inward toward Harney and Malheur Lakes, on the basin's floor. Burns, Oregon, is the only sizable town in this remote, high desert basin.

While most of the basin floor is high and dry, with elevations between 4000 and 5200 feet, Malheur Lake, fed by the Silvies River from the Blue Mountains and the Blitzen River from Steens Mountain, provides a rich and welcome oasis for migrant waterfowl, shorebirds, white pelicans and sandhill cranes. Home to many other species as well, the lake and its wetlands are protected as the Malheur National Wildlife Refuge; during seasons with heavy precipitation or snowmelt, Malheur Lake spills west toward Harney Lake, an ephemeral, salt pan lake that is the topographic sink of Harney Basin.

The Arctic Falcon

Gyrfalcons are the largest and most powerful falcons on our planet, inhabiting Arctic and Subarctic regions of the globe. Those that live near or above the Arctic Circle are white or pale gray in color while more southern subspecies have various degrees of gray or brown in their plumage.

Solitary for much of the year, adult males and females pair up in March and a clutch of eggs is laid by late April, usually on a bare rock ledge or perhaps in an abandoned raven nest. Both parents incubate the eggs and, within two weeks of hatching, the downy young are left to endure the harsh northern climate while the parents hunt for food; it is then that gyrfalcons are most vulnerable to predation, usually by ravens, skuas or Arctic fox. Those that survive to adulthood have little to fear from natural predators; swift, powerful and agile, they are imposing rivals and may live for 20 years or more.

Gyrfalcons feed primarily on ptarmigan but also attack geese, ducks, gulls and a variety of Arctic songbirds; tundra residents such as Arctic hares, ground squirrels and lemmings are also potential victims. These magnificent raptors, in the style of great white sharks, initially stun their prey with a traumatic collision or chase them to ground before making the kill. During the colder months, gyrfalcons are known to hunt along the pack ice, oblivious to the frigid conditions; though nonmigratory, a few may turn up across the northernmost U.S. in mid to late winter.

Vancouver Island Earthquake

Along the Pacific Coast, from southern British Columbia to northern California, three small tectonic plates lie between the Pacific and North American Plates. The Juan de Fuca Plate is the largest, stretching from the center of Vancouver Island to the southern border of Oregon, while the Explorer Plate sits north of it and the Gorda Plate lies off northern California; all three, like the Cocos Plate off Central America and the Nazca Plate along the west coast of South America, are remnants of the oceanic Farallon Plate, most of which has since subducted beneath the North and South American Plates.

On the west side of the three plates, they are spreading from the Pacific Plate along a broken oceanic ridge while, on their east side, they are subducting beneath the North American Plate. Between the spreading zones, each plate also has a transform-fault margin with the Pacific Plate, where the plates are scraping against one another; in addition, horizontal (east-west) faults form the boundaries between the Juan de Fuca Plate and its smaller neighbors. In this complex tectonic region, earthquakes may thus be generated at the subduction zones, along the transform faults or at the faults that separate the three plates.

Yesterday's 6.4 magnitude quake occured off the west coast of Vancouver Island, along the subduction zone and very near the margin between the Explorer and Juan de Fuca Plates. Rather shallow (14 miles deep), it was felt as far away as northern Washington but, fortunately, did not produce significant damage. Of course, there is always the potential for strong quakes in this region and those that occur along the subduction zone could produce a catastrophic tsunami. Hopefully, regularly occuring weak quakes might diminish the risk for such an event.

Washington's Eocene Coast

During the Eocene Period, some 50 million years ago, sediments collected across what is now western Washington. The majority of these deposits were continental in origin, eroded from pre-Cascade uplands to the east; some, especially across southwestern Washington, were marine in origin, deposited in shallow seas as ancestral whales were first returning to the ocean.

Today, these Eocene sediments underlie Puget Sound and the urban areas that hug its shoreline. Continental Eocene deposits, both sedimentary and igneous, also comprise the Olympic Mountains and a mix of marine and terrestrial Eocene sediments have been folded to create the Coastal Range, further south; nearing the Oregon border, younger Miocene deposits also appear in this latter Range.

The modern Cascades, volcanic in origin, are composed of much younger rock, forming from the Miocene (about 20 million years ago) to the present day. The major stratovolcanoes (Ranier, St. Helens, Adams) rose during the Pleistocene (within the last 2 million years) and, as became painfully evident in 1980, are still evolving. Of interest, the Northern Cascades are composed of much older Jurassic magma, intruded some 150 million years ago but lifted and sculpted as the younger Cascades developed.